Transformer winding



April 1932- J. J. FRANK 1,852,805

TRANSFORMER WINDING Filed Oct. 2, 1931 Fig.6.

Inventor: John J". Framk, y Mad/WM H is I Attorhey.

Patented Apr. 5, 1932 UNITED STATES PATENT OFF ICE JOHN J. I'mPITTSII'IILD, IABSAGKUBET'IS, ASSIGNOB '1'0 GENERAL ELECTRIC comm, ACORPORATION O! m YORK MIIOBHER WINDING Application ma 0mm 2, 1931.Serial Io. 500,560.

My invention relates to windings for electrical apparatus, such astransformers, and more particularly to windings of large cross sectionconductor for carrying heavy currents. Some transformers such as areused to furnish current for welding and electric furnace operation havewindings which operate at very low volta e but which carry very largecurrents. S uch large currents make it necessary that the conductorforming the turns of these windings have such large cross section thatit cannot be bent into .the required shape and the turns have sometlmesbeen made up of short heavy metal plates welded or brazed end to end asdisclosed, for example, in United States Patent No. 1,723,840, issuedAugust 6, 1929, on an application filed by Locke H. Burnham. This methodof forming a winding avoids any bending of the conductor but results ina winding having a considerable number of joints which are expensive tomake and which may have some objectionable resistance. The generalobject of the present invention is to provide an improved transformerwinding and a method of forming it, the windin conductor being of largecross section an having few joints.

The invention will be better understood from the following descriptiontaken in connection with the accompanying drawings in which Fig. I is avertical sectional view of a transformer of the air blast type having awinding formed in accordance with the invention; Fi 2 is a perspectiveview of a section of t e winding; Fig. 3 is an edge view of the winding;and Figs. 4, 5 and 6 are views of metal blanks from which the windingmay be formed.

Like reference characters indicate similar parts in the differentfigures of the drawings.

The transformer 10 shown in Fig. 1 is of the air blast type and includesa magnetic core 11 with a high voltage winding 12 formed in two sectionsand a low voltage Windin 13 formed in three sections. These threewinding sections are alike, one of them being shown in'detail in Fi s. 2and 3. The two end turns 14 and 15 0 each section of the low voltagewinding are provided with terminals 16 and 17 respectively so that thesections may be connected in series or multiple as desired. The other orinner turns 18 are similar to the end turns 14 and 15 but without theterminals.

As shown in Figs. 2 to 6 inclusive, which are about half size ascompared with Fig. 1, each turn of the winding sections 13 is made froma blank in the form of a heavy flat metal plate, preferably copper, withan opening 19 for the winding leg of the core 11. Each blank is thus acontlnuous turn surrounding its opening 19. These blanks may be formedin any desired way as by casting them or by shearing, cuttin or punchingthem from solid flat metal p ates or sheets.

The turns in the finished winding, as indicated in Figs. 2 and 3, arepreferably spaced to permit heat to be readily dissipated. Each turnincludes a flat portion extending nearly around the space 19 occupied bythe winding leg of the core and these flat portions are connectedtogether in series by crossovers 20. Each of the blanks 14, 15 and 18 iscut or severed at one side to change it from a closed turn to an openturn with two ends 21 and 22. Each of the ends 21 at one side of theseries of cuts is bent at an angle to the plane of its turn to meet theend 22 at the opposite side of the cut in the adjacent turn, the bentends of the turns thus forming the crossovers 20 between turns. Each ofthe crossovers 20 and the end 22 of the adjacent turn are fused togetheras by welding or brazing as indicated in Figs. 2 and 3.

After an end 21 of a turn has been bent out of the plane of the rest ofthe turn, it does not, of course, reach quite as far around the axis ofthe turn as it did before being bent. For this reason, the cuts in thetwo turns must be displaced sli htly as indicated in Fig. 3 in orderthat tEe bent end 21 of the first turn may reach the end 22 of the nextturn. The cuts are therefore progressively displaced in successive turnsabout their common axis. Thus, the first turn 15 may be cut as indicatedby the line a in Fig. 5, successive intermediate turns 18 as indicatedby the lines 6 and 0 in Fig. 6 and the last turn 14 by the line (1 asindicated in Fig. 4. Inasmuch as no crossover is requiredbeyond the lastturn 14, another cut e is made in this turn and the section or end 21 ofthis turn between the cuts (1 and e is removed.v 5 The invention hasbeen explained by describing and illustrating a particular form ofwinding and method of formin it, but it will be apparent that changesmay made with out departing from the spirit of the invention and thescope of the ap ended claims.

What I claim'is new an desire to secure by Letters Patent of the UnitedStates, is,-

1. .The method of forming a windin for electrical ap aratus from flatmetal bIan in the form of closed turns, said method including the stepsof cutting each of said turns at one side to form open turns, said cutsbeing progressively displaced in successive turns about their commonaxis, bending at least one end of each turn except the last to meet anend of the next turn, and fusing the meeting ends together.

2. A winding for electrical apparatus, said winding including turnshaving spaced flat 2 portions, each turn except the last having one endbent and connected to an adjacent turn by a fused joint, said fusedjoints being r0- gressively displaced in successive turns a out thecommon axis of the turns. In witness whereof, I have hereunto set myhand.

JOHN J: FRANK.

